CSA 3.7-2017 Non-recirculating direct gas-fired heating and forced ventilation appliances for commercial and industrial application.
4.10 Manual gas valves
Manual gas shutoff valves shall comply with the applicable construction provisions of the Standard for Manually Operated Valves for Appliances, Appliance Connector Valves and Hose End Valves, ANSI Z21.15
• CGA-9.1, Lever Operated Pressure Lubricated Plug Type Gas Shut-Off Valves, CSA 3.11, Lever Operated Non-Lubricated Gas Shut-Off Valves, CGA-3.16, or the Standard for Combination Gas Controls for Gas Appliances, ANSI Z21.78 • CSA 6.20. Disc-type manual gas shutoff valves shall be of the non- displaceable rotor type for both individual and combination type valves.
Manually operated burner, pilot, and main shutoff valves shall be of the 3/4 turn type supplied with a lever handle, clearly indicating the “on” and “off” positions, and shall be suitable for the pressure used.
A heater shall either have a manual gas shutoff valve provided in an accessible location for turning on or shutting off the gas to the main burner(s) or an accessible switch on the appliance for manually interrupting the ungrounded leg of the electrical power to both appliance automatic valves, provided that the heater does not have a continuous pilot ignition system and it has two automatic valves for controlling main burner gas flow.
Either means for shutting off gas to the main burner(s) shall bear a Class Ill marking clearly indicating the “on” and “off” positions.
The accessible switch shall apply only to appliances with input rates of 400,000 Btu/h (117 228 W) or less per combustion chamber.
A manual gas shutoff valve shall be provided downstream from the last main line gas safety shutoff valve. A test gauge connection shall be furnished between the last main gas safety shutoff valve seat and the manual gas shutoff valve. The connection shall be a 3/s in or 1/4 in NPT plug or cap with cleanly cut taper pipe threads in accordance with the Standard for Pipe Threads, General Purpose (Inch), ANSI/ASME B1.20.1. If the plug is of the slotted type, it shall also incorporate square or hex flats, or:
a) a tapping sealed by a Y8 in or Y4 in NPT plug or cap as specified above; or
b) a hose fitting that incorporates a captured sealing means.
The fitting shall have a minimum length of 0.355 in (9.02 mm) and a 0.355 in (9.02 mm) maximum! 0.335 in (8.50 mm) minimum outside diameter.
A manually operated pilot shutoff valve shall be located upstream from all pilot controls and downstream from the main gas supply connection to the heater.
4.11 Gas supply lines
The following construction provisions apply to the gas supply lines used within a heater.CSA 3.7 pdf download.